( 271 ) 



The results of some recent iii\estii>,;itioiis ') ;ill lend to conlirni the 

 hypothesis that the causation of anomalous tlispcrsion is a general 

 |)ropertY of matter. Thence, e\en highly rarefied gases, whose density 

 is unequally distributed, cause some kinds of rays to be considerably 

 deflected. All the conclusions arrived at by Youno, Lockvkr and 

 others, as to the thickness of the various concentric layers in the 

 solar atmosphere, the velocities of the prominences, the displacement 

 of matter in the sun-spots, the dissociation of elements in the Sun 

 etc., must be sacrificed in so far as they are based on the erroneous 

 notion that the objects are situated in the exact direction where they 

 are seen b}' us. 



A. Schmidt '^) has gone so far as to demonstrate that the sliar[)ly 

 defined circular outline of the Sun's disc is no proof of the Sun being 

 a spherical body. Owing to the cur\'ilinear propagation of the rays, 

 a gradually fading luminous mass of gas might apj)ear to us as a 

 sharplv outlined disc. 



We may therefore be allowed to consider the Sun an uncoidined 

 gaseous mass. 



By taking also into account the laws of the anomalous dispersion 

 of light, we succeeded in finding explanations for almost all the 

 phenomena observed on the surface of the Sun and on its edge '). 

 We felt justified in starting from the simple supposition that in the 

 gaseous, unlimited body of the Sun, the several elements are not 

 locally separated but intrinsically mixed. Perhai)S future investigations 

 may lead us to admit that in the solar body some elements are 

 locally separated, but I thiidc that the })resent state of our knowledge 

 regarding the properties of sun-spots, taeniae and prominences does not 

 warrant such an assum})tion. 



Our new conception of the Sun leaving no longer any room for 

 the hypothesis of a periodical activity manifesting itself in violent 

 eruptions, we are naturally led to iiKjuire ^vhether all the phenomena 

 attributed to this cause, may equally well — perhaps better — l)e 

 explained as elfects of the dispersion of light. 



The following data may assist in the elucidation of this (juestion. 



^) 0. LuMMEK iind E. Pringsiieim, Zur anomalen Dispersion dor Case, Pliysik. 

 Zeitschr. 4, S. 430-431. 1003. 



H. Kbert, Die anomale Dispersion dor Melalldiinipfe. Phys. Zcitsclir. 4, S. 473— 47G. 



H, Ebert, Die anomale Dispersion und die Sounenpluinomene, Aslr. Nachr. IG^, 

 S. 104—195. 



2) A. ScHMmT, Die Slrahienbrechung auf der Sonne. Slnllgar', ISII'. 



■') W. 11. Julius, Proc. Roy. Acad. Anisl. II, p. :>!:>- .^S8 ; 111, p. 195 203; 

 IV, p. 102—171; 589— Ü02; 002- GOG. 



